Correct AC Rad Core Support For 1968 427 390HP?

[Joseph M.]

My car started out in life as a 1968 427 390hp non AC car, and over the last year, I have found and installed all of the hard to find 1968 only AC parts in the interior and the correct 68 only evaporator case assembly. The remaining job that I have left is to install the correct 68 only big block AC radiator core support, correct condenser and mounting brackets, and correct AC lines with the correct hose clamps which I have already collected. Even though the parts cost much more, I could not stand the thought of installing an aftermarket JIP AC system even though it would have been at a 1/3 of the cost in parts of what I paid. Recently I picked what I was told and appeared to be the correct AC Radiator Core Support according to the 1968 Corvette assembly manual for my 1968 Corvette 427 390HP. While this unit has the correct 1968 condenser AC line holes and the correct brass copper radiator support mounts for my existing new 427 radiator, I don’t see three out of the four holes required for mounting my original fiberglass 427 fan shroud. On AIM UPC L36 A11, the bottom hole below item 4 appears to be the correct lower fan shroud mounting hole which is on this core support but the remaining three are missing. On AIM UPC L36 A11 lower right this hole has a line pointing to it and it shows 7/16 + - 1/64. Also, on AIM UPC C60 B1, the original 68 condenser correct mounting brackets line up with all of the existing holes which is good. End the end, maybe this 1968 AC core support was used for a slightly diffent application but I'm hoping that you will tell that drilling the remaining three holes will make it correct for my applcation. In addition, I got the impression from the assembly manual that the non AC and AC 427 390hp fiberglass fan shrouds are the same so I’m hoping that you can confirm if this is correct. Furthermore, I have attached a picture of the core support so you can get a better idea of what I’m talking about.
Thanks!
Joe

[Wayne W.]

Re: Correct AC Rad Core Support For 1968 427 390HP?

Is a hole ever really missing, or is it really there and you just cant see it.

[Bryan M.]

Re: Correct AC Rad Core Support For 1968 427 390HP?

I could be a support for a small block with a/c that used the metal shroud. I believe the early 68 with a/c small blocks used the metal shroud.

[Joe L.]

Re: Correct AC Rad Core Support For 1968 427 390HP?

Thanks!
Joe

Joe----

Instructions for drilling the holes for the shroud fasteners are contained in the AIM (UPC L-36).

The big block fan shrouds for C-60 and non-C-60 applications were the same.

[Joseph M.]

Re: Correct AC Rad Core Support For 1968 427 390HP?

Hi,

There are definitely no other holes present.

Thanks!

[Joseph M.]

Re: Correct AC Rad Core Support For 1968 427 390HP?

Bryan,

According to the 1968 assembly manual and from what I have been told, the seal stapled to the air baffle that is bolted to the top of the core support only came on big block Corvettes in 68 so I'm thinking that either someone put this on the top of the small block core support or more likely it is a big block core support because the mounting screws, the baffle plate and seal is the same as on my 427 390 non AC core support.

[Joseph M.]

Re: Correct AC Rad Core Support For 1968 427 390HP?

Joe,

In the assembly manual, it shows that the small block and big block with AC set (AIM C60 B3) looked very similar so is it possible that this core support is actually out of a small block with AC which used the round steel shroud that connected at the top center and on the plate at the bottom? On the contrary, on page AIM UPC C60 B4, it shows that fan shroud on the small block with AC also bolted up to the core support similar to my original 427 setup. It sounds like from your reply that all I will have to do to have the correct core support for my 68 Big Block is drill the three remaining holes which will be great!

Thanks!
Joe

[Terry M.]

Re: Correct AC Rad Core Support For 1968 427 390HP?

Citing page numbers (such as H-307) in the assembly manual is not useful for all of us. Different versions of the AIM have different page numbers, and the originals don't have page numbers at all.

If you wish to cite a page in the AIM (Assembly Instruction Manual) you need to look in the "information block" for the UPC (Universal Product Code) number -- such as Joe Lucia cites UPC L36 and then cite the sheet number (shown below the UPC number in the information block) such as A1 or B3 or whatever.

Pages in the AIMs are organized by UPC number and most, but not all, manuals have a contents list in the front. There is a lot of information on the AIM pages, but one must learn how to use them. One can not learn that from this board. There have been several stories in The Restorer about how to use them. There are also limitations to what the AIM will tell you, but unless one understands what that book is, and is not, one will not understand those limitations.

[Joseph M.]

Re: Correct AC Rad Core Support For 1968 427 390HP?

Terry,

Thank you for the information! I have updated my posts with the correct UPC and sheet number. Won't happen again!

[Joe L.]

Re: Correct AC Rad Core Support For 1968 427 390HP?

Joe,

In the assembly manual, it shows that the small block and big block with AC set (H-307) looked very similar so is it possible that this core support is actually out of a small block with AC which used the round steel shroud that connected at the top center and on the plate at the bottom? On the contrary, on page H-306, it shows that fan shroud on the small block with AC also bolted up to the core support similar to my original 427 setup. It sounds like from your reply that all I will have to do to have the correct core support for my 68 Big Block is drill the three remaining holes which will be great! As for the instructions for drilling the holes, I'm not familiar with the AIM (UPC L-36) so please let me know what that is and where I can get it. Also, the assembly manual appears to have the correct instructions for drilling the remaining 3 holes on page H-307. Will this be sufficient or is the AIM (UPC L-36) a better way to go?



Thanks!
Joe

Joe-----


The fact that the AIM shows the location for drilling the fan shroud fastener holes STRONGLY IMPLIES that, at least, some, if not all, of the supports did not have these holes drilled. If they were all drilled there would have been absolutely no reason to specify the hole locations in the AIM. What really surprises me is that the holes were not pre-drilled. With a core support there is no problem with having extra holes; lots of core supports have holes which may not be used for particular applications.

So, I really think that all you need to do is to add the holes----just like they did for at least some cars at the factory.

[Bryan M.]

Re: Correct AC Rad Core Support For 1968 427 390HP?

Bryan,

According to the 1968 assembly manual and from what I have been told, the seal stapled to the air baffle that is bolted to the top of the core support only came on big block Corvettes in 68 so I'm thinking that either someone put this on the top of the small block core support or more likely it is a big block core support because the mounting screws, the baffle plate and seal is the same as on my 427 390 non AC core support.

I believe the small blocks came with the hood air dam too.
I might be wrong but the baffle on your support looks like a small block hood air dam to me. Hopefully someone else will chime in.

[Joseph M.]

Re: Correct AC Rad Core Support For 1968 427 390HP?

Joe,

Being that this core support has the stapled seal along the top of it (L36 A12), do you think this core support started out life in a big block 68 AC Corvette or a small block AC car with a different shroud configuration?

[Wayne W.]

Re: Correct AC Rad Core Support For 1968 427 390HP?

We have to be very careful with statements about `68s. There were so many running changes, it is difficult to know what is and what aint.

Here is a late SB with AC. Note the rubber dam, the shroud extension.

[Wayne W.]

Re: Correct AC Rad Core Support For 1968 427 390HP?

Joe-----


The fact that the AIM shows the location for drilling the fan shroud fastener holes STRONGLY IMPLIES that, at least, some, if not all, of the supports did not have these holes drilled. If they were all drilled there would have been absolutely no reason to specify the hole locations in the AIM. What really surprises me is that the holes were not pre-drilled. With a core support there is no problem with having extra holes; lots of core supports have holes which may not be used for particular applications.

So, I really think that all you need to do is to add the holes----just like they did for at least some cars at the factory.

I would think that the early supports that were intended for metal shrouds, probably didnt have the holes pre-drilled. The later that were to have the fiberglass shrouds could have already been drilled. I dont know. The fiberglass shroud is the same basic shroud that was used maybe very late in `67 on BB cars. I am sure it is essentially the same as the service shroud for the 67 BB.

[Joe L.]

Re: Correct AC Rad Core Support For 1968 427 390HP?

Joe,

Being that this core support has the stapled seal along the top of it (L36 A12), do you think this core support started out life in a big block 68 AC Corvette or a small block AC car with a different shroud configuration?

Joe-----


I did not know if the shroud you had pictured was a used original, a used SERVICE shroud, or an NOS shroud (that had sat around somewhere for a long time in a "wear-and-tear" environment). Being that it's, apparently, a used original shroud, it had to have come from an EARLY 68 small block with C-60 and/or M-40. Those would be the only 68's that did not use the fiberglass shroud which would have required the 4 holes be drilled at St. Louis. No 1968 big block ever originally used any shroud other than the fiberglass. The small block metal shroud could not have been used for a big block application since it would not fit correctly without modification.